YOUR HOME; Solar Panels Are Making More Sense

''BY the time you leave this room, I would like to have every one of you convinced that solar energy can make sense in New York,'' said Richard Perez, a research professor at the State University of New York at Albany, addressing the April 16 meeting of the New York chapter of the Association of Energy Engineers in Manhattan. While Dr. Perez's audience that day was far from being a hard sell -- the association is dedicated to promoting the principles and practices of energy conservation and energy-efficient design -- persuading the public may be more difficult.

After all, as Dr. Perez was quick to point out, a common misconception among professionals and consumers is that while solar power might make sense in places with lots of open space and abundant sunshine, it is less likely to be cost-effective in the densely populated, less-sunny Northeast.

''Everybody tells you that there aren't enough sunny days in New York compared to places like Florida, California and Arizona,'' he said. ''But when you talk in terms of the potential energy yield from solar on an annual basis, there is only a 35 percent difference between New York City and Tucson.''

In fact, Dr. Perez said, because of increases in the efficiency of solar panels, decreases in their cost, changes in metering policy and financial incentives available to homeowners who install solar energy systems, there is easily enough sunshine in the New York area to make the installation of a solar electric system an attractive proposition in many homes.

Fredric Goldner, president of the New York chapter of Energy Engineers, agreed. ''Generating electricity by using solar energy has always made sense,'' he said. ''But it makes more sense now than most people know.''

Mr. Goldner said that in a standard residential application, solar panels -- known as photovoltaic panels -- are typically installed on a roof facing in a southerly direction.

Once the panels are installed, Mr. Goldner said, they are connected to a device known as an inverter. The inverter, usually installed inside the house near the main electrical panel, converts the direct current produced by the photovoltaic cells to alternating current, the type used in homes. The wire from the inverter bearing the alternating current, he said, is then connected to the main power supply in the house. At that point, he said, the power being supplied by the solar panels is indistinguishable from power being supplied by a utility company.

Once the system is running, Mr. Goldner said, the power that must be purchased from the utility company is directly reduced by the amount of power generated by the solar electric system. In other words, if on a sunny day the system provides all of the power needed in a particular house, the homeowner would not pay for any power from the utility.

Of course, Mr. Goldner pointed out, even the most efficient solar energy system is not going to produce energy at night and may be producing energy when it is not needed. And while that has always been a lightning rod for criticism of such systems, recent changes in the way that utility companies deal with energy produced by customers have all but eliminated those issues.

Mr. Goldner said that utility companies in New Jersey, New York and Connecticut must now allow for net metering, which provides that excess electrical energy produced by the solar panels is sent from the inverter backward through the meter to the utility company.

''That means that if you are out at work on a sunny day, or go on a two-week skiing vacation, and aren't using any electricity, the power being created by the solar panels is going back into the grid to the utility company,'' Mr. Goldner said. ''And the best thing is that the utility company is crediting you for any power you produce at the same retail rate you pay.''

In other words, he said, every kilowatt-hour of electricity produced by a solar energy system ends up being used to the advantage of the homeowner, either as power to run appliances when the homeowner is there or as a dollar-for-dollar credit provided by the utility company for power that is not being used. ''When you're producing more power than you're using, your meter actually runs backward,'' Mr. Goldner said. ''It's a beautiful thing to see.''

Gay Canough, president of ETM Solar Works, a solar energy contractor in Binghamton, N.Y., said homeowners interested in having solar energy systems installed in their homes should size the system to their specific power needs and location.

For example, she said, for a house in Binghamton, where there is an average of 1,400 hours of sunlight each year, a customer who used 3,000 kilowatt hours of power each year would need a 2.64-kilowatt system to meet all his energy requirements after the benefits of net metering are taken into consideration. For a house on Long Island, where there is an average of 1,600 hours of sun each year, she said, a customer who had the same energy requirements would need a 2.34-kilowatt system.

Generally speaking, Ms. Canough said, a standard residential solar energy system cost about $10 per watt, including installation. That means that a 2-kilowatt system, which would take up about 200 square feet of roof space, would cost about $20,000. ''And the installation time is pretty short'' -- just a few days in most cases -- she said.

Dr. Perez said that financial incentives available in New York and New Jersey could make the installation of a solar energy system even more attractive.

For example, he said, the New York State Energy Research and Development Authority provides rebates of $3,000 a kilowatt, up to a maximum of $7,500. ''That means that on a 2-kilowatt system, Nyserda will pay the first $6,000,'' Dr. Perez said.

He added that there was also a New York State tax credit of 25 percent on the remaining difference. So, he said, a 2-kilowatt system that costs $20,000 would cost only $14,000 after the rebate. And since the homeowner would be entitled to a 25 percent state tax credit on the $14,000, that would further reduce the ultimate cost of the system by $3,500. Moreover, Dr. Perez said, Nyserda also provides ''buydowns'' on the interest rate for loans used to install a solar energy system. So if the remaining $10,500 needed to install a 2-kilowatt system is borrowed at an interest rate of 8 percent, Nyserda will pay 4.5 percentage points of the interest for the first five years.

In fact, Dr. Perez said, after all the incentives, tax benefits and utility cost savings have been taken into consideration, it should cost the homeowner only an additional $10 to $20 a month to pay for a $20,000 solar energy system over a period of 20 years. ''And that is assuming that energy costs remain constant,'' he said, adding that if utility costs increase, the homeowner's net monthly savings will increase as well.

Incentives for homeowners on Long Island are even more generous.

Bert Cunningham, vice president of communications for the Long Island Power Authority, which provides electrical power to residents of Nassau and Suffolk Counties and to the Rockaway Peninsula in Queens, said that for systems installed by July 31, 2002, LIPA would provide a rebate of $6 per watt for systems up to 10 kilowatts in size. That means that on a 2-kilowatt system, the rebate would be $12,000. (After July 31, the rebate will be $4 per watt.) In addition, Mr. Cunningham said, homeowners are entitled to the 25 percent tax credit on the balance of the cost. Moreover, he said, LIPA will also arrange for a buydown of the interest rate on a loan used to finance a system to 6 percent.

New Jersey also offers incentives for installing solar energy systems in homes. At present, the state provides a rebate of $5 per watt, with rebates capped at 60 percent of the cost of the system. And while Connecticut has no rebate programs in place, the state does allow municipalities to offer property tax credits for installing renewable energy systems.

Additional information about incentives for renewable energy systems are on the Internet site of the Database of State Incentive for Renewable Energy: www.dsireusa.org. Additional information and links to other sites can be found on the Web site of the American Solar Energy Society: www.ases.org.

Correction: May 19, 2002, Sunday The Your Home column on May 5, about solar energy systems, misstated the title of Fredric Goldner, a member of the Association of Energy Engineers who commented on the increased efficiency of generating power with solar panels. He is a past president of the New York chapter; its current president is Asit Patel.